The present invention relates to the field of centrifuges and more particularly to a centrifuge rotor for sorting particles by the process of centrifugal elutriation.
Among the many methods known for separating biological cells by reference to their comparative sedimentation velocities, centrifugal elutriation is becoming a widely favored method. Centrifugal elutriation, which has also been called "Counter Streaming Centrifugation" in some scientific literature, is a continuous flow process whereby liquid buffers are pumped through a cavity within a rotor cell as counterflow mediums in the process of separating and collecting the particles of interest.
In the design of prior art elutriation rotors, a typical practice was to house the elutriation cells in cavities in the rotor which were disposed symmetrically in relation to a spindle fixedly mounted at the central axis of the rotor. In addition to providing support for the rotor on the drive shaft, the spindle also contained the necessary inlet and outlet fluid passageways for conveying fluids to the rotor during its rotation. These fluids were introduced and recovered through ports provided in a rotatable seal extending into a stationary bearing positioned at the upper end of the spindle. Fluids introduced at the inlet port of the stationary bearing enter the inlet passageway of the spindle. The inlet passageway of the spindle intersects with a passage through the rotor which, in turn, communicates with the inlet passageway of the elutriator cell, leading to the entrance to the elutriation chamber (i.e., separation chamber). The outlet portion from the cell communicates with a passage through the rotor that, in turn, intersects with the outlet passage through the spindle.
The foregoing arrangement employs a relatively large number of passageways and aperture interfaces. This necessarily increases the risk of leakage through O-ring failure or misalignment of passageway apertures. The design also imposes a relatively severe constraint on the length of the elutriation cell that can be employed thereby limiting the volume as well as the shape of the separation chamber that may be used therein.